Plate clamp for securing and positioning printing plates on printing cylinders



W. F. HUCK PLATE CLAMP FOR SECURING AND POSITIONING May 25, 1943.

PRINTING PLATES 0N PRINTING CYLINDERS 1------ {iii}... 1.. Ii:

I I I I ll fi k l lll' lll II II llll lllll lllll Ir 1 [III llll II IIIllll llll I|ll llll TlT III I lill Filed Aug. 3, 1940 rlluut PatentedMay 25, 1943 PLATE CLAMP FOR SECURING AND POSI- TIONIN G PRINTING PLATESON PRINTING CYLINDERS William F. mick. men-none mu, N. Y., assignor toR. Hoe & 00., Inc., New York, N. Y., a corporation or New YorkApplication August 3, 1940, Serial No. 350,988

10 Claims. (Cl. 101-4151) This invention relates to plate holdingdevices, and more particularly to method and means for locating alithographic printing plate or the like in a desired position on aprinting cylinder and quickly securing it.

An object of the invention is to provide plate clamping mechanismwhereby a plate may be attached to or removed from a printing cylinderquickly and with little efiort on the'part of the operator.

Another object is to provide in a printing cylinder, a plate clampingmechanism arranged to accurately position plates to which clamping Ibars have previously been attached and positioned in definite respect toa printing form on the plate. by means of a registering device.

" Still another object of the invention is to provide a method and meansfor accurately positioning a series of multicolor printing plates, eachon one of a plurality of printing cylinders, with the printing formscarried by each of the plates in corresponding position on eachcylinder, and quickly securing the plates in position and under tension.

Still another object of the invention is to provide a plate clampingmechanism that will ac-' curately positiona plate in a desired locationon a printing cylinder without the necessity of sharply bending the edgeof the plate.

It is also an object of the invention to provide 'a plate clampingmechanism of generally improved construction, whereby the device will besimple, durable and inexpensive in construction, as well as convenient,practical, serviceable and efiicient in its use.

With the foregoing and other objects in view that will appear as thedescription proceeds, the invention resides in the combination andarrangement of parts, and in the details of construction and in themethod of operation hereinafter described and claimed, it beingunderstbod that various changes in the precise embodiment of theinvention herein disclosed may be made within the scope of what isclaimed without departing from the spirit of the'invention. V

'The preferred embodiment of the invention is illustrated in theaccompanying drawing, wherein:

Figure 1 is an end view of a printing cylinder having plate clampingmeans made in accordance with the invention, certain parts being brokenaway, and certain parts being shown in section as indicated by lines I Iof Figure 2;

Figure 2 is a longitudinal view showing a portion of the cylinder asseen in the direction of arrow 2 of Figure 1; and

Figure 3 is a longitudinal view of another portion of the printingcylinder as seen in the direction oi! arrow 3 of Figure 1.

In large printing plants where operations are standardized to a greatextent, it is desirable to so lock the printing plates on the cylinders,that the printing forms will always occupy identical positions on thecylinders, this being particularly necessary in multicolor printing,where several impressions are successively made on the same sheet and itis necessary that the impressions be in accurate register.

The plate clamping mechanism herein disclosed provides means foraccurately positioning the printing forms on the cylinders Without thenecessity for adjustment of the plate after it is placed on thecylinder, and the operation may be performed in a much shorter time thanwhen using a clamping device of the types heretofore employed.

Referring to the drawing which shows a portion of a printing cylinderadapted to the use of the. invention, H indicates the printing cylinder,and one of its bearers I0 is broken away to bet- I ter show a recess I2arranged to receive plate clamping mechanism for one edge of a printingplate l4 which is wrapped about the cylinder,

itsopposite edge extending to another recess [5 in which a secondclamping mechanism having jaws i6 and il is mounted. In the preferredmethod of operation, the printing cylinder shown on the drawing will berotated in a counterclockwise direction, as indicated by the arrow inFigure 1, and the leading edge of the plate will be secured to aclamping fixture l3, and the trailing I edge of the plate will be heldby the jaws l6 and ll. plate that are held by the clamping devices arereferred to herein as the leading and trailing" edges for convenience indistinguishing them, but it will be understood that in cases where it ismore convenient to operate the printing cylinder in the reversedirection, the terminology applied For this reason, the two edges of theprinting a proper location of these clamping bars on the Plate may beeffected by the use of a registering device shown in United StatesPatent Number 2,234,170, granted March 11, 1941, which discloses atable-like plate support having a registering device, whereby a seriesof plates having similar printing forms may be identically positioned onthe support. A holder is provided which extends across the support andin which the lower clamping bar is is placed. Thus, when the plate iscorrectly located and the upper clamping bar I6 is placed in positionand the bars are secured to the plate, these clamping bars will be inproper relation with the printing forms, to produce correctly registeredprinting.

The lower clamping bar I3 is preferably formed with shoulders 2| and 22on its lowermost side, and with a rabbet 23 on its uppermost side. Theupper clamping bar I6 is formed to fit into the rabbet 23, and has anextended lip 24 that coopcrates with the jaw surface 26 on the lowerclamping bar |9 to grasp the plate. Clamp screws 21 which are threadedinto the lower clamping bar, when tightened, serve to rigidly secure thebars to the plate.

The clamping fixture i3 is provided with adjusting screws 26 which arescrew threaded through suitable holes therein, whereby its position inthe recess I2 may be adjusted.

The fixture I3 is held in the cylinder by means of screws 29 that passthrough bushings 3| and are screw threaded into the cylinder body. Thebushings 3|, which are loose in elongated openings 32 in the fixture I3,have flanges 33 which engage the lower surfaces of the cutaway portions34 of the fixture l3. The openings 32 are made wide enough to permit alimited longitudinal adjustment of the fixture by means of adjustingscrews 30 which are screwed into the fixture and are turned so theirheads abut against the bearrs It. It will be seen that this arrangementpermits peripheral adjustment of the fixture l3 in the cylinder recessby turning the screws 28, and longitudinal adjustment by means of thescrews 30. Both of these adjustments are usually employed for initialadjustment only and are not used during ordinary operation of themachine. The fixture I3 is formed with a slot having a side recess 36arranged to receive the shoulder 22 of the clamping bar l9, and anoppositely disposed recess 31 is arranged to receive the shoulder 2| ofthe clamping bar |9. Clearance between the clamping bar and the fixtureI3 is preferably provided, so that the bar may be moved counterclockwisein respect to the cylinder to a slight formed in a lever 6| which ispivotally supported on the pins 33, and having a projection 62 thatextends through an opening 53 in the jaw plate extent, and then swungoutwardly without loosening any of the parts. Dowel pins 35 are securedin the clamping fixture l3, and slots 40 are provided in the under sideof the clamp bars I! for the reception of pins 35 to insure accuratealignment of these parts when the plate is placed on the cylinder.

Referring now to the clamping mechanism for the trailing edge of theplate, the jaw I1 is formed on the outer edge of a jaw plate 38, ofwhich there may be several aligned in the recess l5. These jaw platesare pivotally supported on pins 39, held in blocks 4|, secured in thebody of the cylinder II by means of screws 42. Each jaw plate has pivotpins 44 which pivotally support a jaw member 46.

For each jaw member, a compression spring 41 is arranged in a bore 48 inthe cylinder I and its outer end abuts against the bottom of a recess 4936 to engage the jaw member.

An operating shaft 64 is provided which extends lengthwise of thecylinder, and it is formed with an outer end having flattened surfaces66 to be engaged by a wrench 61 (Figure 3) for manual operation. Pins66, preferably having concave surfaces shaped to conform to theperipheral surface of the shaft 54, are secured thereto by means ofscrews 66, and rollers 6| are rotatably supported on the pins 68 androtate in suitable slots 62 cut in the shaft.

From the foregoing description, it will be understood that the springs41 tend to move the jaw members 46 and with them the jaw plates 36towards the right, as shown in Figure 1. when the rollers 6| carried bythe shaft 64 are in the position indicated by the dotted lines, each jawmember 46 is also in the position shown by dotted lines. Rotation thenof the shaft 54 in counter-clockwise direction will first engage the jawmembers 46, and, due to the spring pressure on the levers 5| and theresulting pressure of their projections 62 on the jaw members 46, the

jaw plates 36 and the jaw member 46 will be swung together about thepivot 33 towards the position shown in full lines in Figure l, but wheneach jaw plate reaches the limit of its travel, its jaw member 46 willthen turn on its pivot 44 to the position shown in full lines, whereinthe jaws are open and the edge of the plate may be inserted betweenthem.

In applying a clamping bar IS with a plate secured thereto, ashereinbefore described, to a printing cylinder, the clamping bar isplaced in the clamping fixture |3 by first inserting the shoulder 22 inthe recess 36, and then swinging the bar into place, so that theshoulder 2| engages in the recess 31. The cylinder is then rotated andthe plate wrapped around the cylinder surface until the trailing edge ofthe plate is in the position shown in Figure 1, whereupon the shaft 54is turned counter-clockwise, moving the jaws l6 and I! into position toengage the trailing edge of the plate as shown in full lines inFigure 1. Then, by turning the shaft 54 in a clockwise direction, therollers 6| move upwardly and when the rollers 6| move upwardly along thejaw members 46, the action of the springs 41 will cause the jaws l6 toengage the plate and press it against the jaws l1. When the jaws arefirmly engaged, further rotation of the shaft 64 will permit the springs41, acting through the jaw members 46 and their pivot pin 44, to swingthe jaw plates 36 clockwise on their pivot pins 38, thus imposing a pullon the trailing edge of the plate which secures it firmly to thecylinder.

From the foregoing, it will be seen that when printing plates havingclamping bars located in proper relation to printing forms thereon, aresecured on similar printing cylinders, or successively on a singlecylinder by means herein disclosed, the resulting printing will be inaccurate register, and that, when employing this invention, plates canbe applied to and removed from a printing cylinder in much less timethan by methods heretofore employed.

It will also be seen that with the plateclamping mechanism hereindisclosed, the edge of the plate is engaged without bending it sharplyas is necessary with most plate clamps heretofore used, and inconsequence, when the invention herein disclosed is employed, a plateafter being removed from the cylinder is perfectly flat and can beconveniently stored, also, if desired, the plate then may be used on anentirely difierent press, which might not be possible if one or more ofthe edges of the plate had been bent;

It will be understood that the invention may be embodied in otherspecific forms without departing from the spirit or essential attributesthereof, and it is therefore desired that the present embodiment beconsidered in all respects as illustrative and not restrictive,reference being had to the claims rather than to the foregoingdescription to indicate the scope of the invention.

What I claim is: v

1. In a plate clamping device for securing a flexible printing plate onthe periphery of a cylinder, means for securing an edge of the platerelative to the cylinder, a plurality of first jaw members movablycarried by the cylinder and having-first jaws to engage the oppositeedge of the plate on the cylinder, a plurality of second jaw memberseach movably supported on a first jaw member and having second jawscooperating with the first jaws to engage the said opposite edge of theplate on the cylinder, a movable member for operating the second jawmembers to open the jaws, and pressure-imparting means operable inopposition to the movable member and continuously coacting with eachpair 'of jaw members for closing the jaws and tensioning the plate whenthe movable member is moved in a direction to release the jaw members.

2. In a plate clamping device for securing a a flexible printing plateon the periphery of a cylinder, means for securing the leading edge ofthe plate relative to the cylinder, a plurality of first jaw membersmovably carried by the cylinder and having first jaws to engage thetrailing edge of the plate on the cylinder, a plurality of second jawmembers each movably supported on a first jaw member and having secondjaws cooperating with the first jaws to engage the trailing edge of theplate on the cylinder, a movable member for operating the second jawmembers to open the jaws, and pressure-imparting means continuouslycoacting with the second jaw members and operable in opposition to themovable member whereby upon movement of the movable member in adirection to release the jaw members the jaws are closed to grip thesaid opposite edge of the plate and then the jaw members are movedrelative to the cylinder to tension the plate on the cylinder.

3. In a plate clamping device for securing a flexible printing plate onthe periphery of a cylinder, means for securing an edge of the platerelative to the cylinder, a plurality of first jaw members pivotallyconnected to the cylinder and having first jaws to engage the oppositeedge of the plate on the cylinder, a plurality of second jaw memberseach pivotally supported on a first jaw member and having second jawscooperat- 4. In a plate clamping device for securing a flexible printingplate on the periphery of a cylinder, means for securing an edge of theplate relative to the cylinder, a plurality of first jaw memberspivotally supported on the cylinder and having first jaws to engage theopposite edge of the plate on the cylinder, a plurality of second jawmembers each pivotally supported on a first jaw member and having secondjaws cooperating with the first jaws to engage the said opposite edge ofthe plate on the cylinder, a movable member for operating the second jawmembers to open the jaws, and pressure-imparting means continuouslycontacting the second jaw members and operable in opposition to themovable member. whereby upon movement of the movable member in adirection to release the jaw members the second jaw members are movedrelative to the first jaw members to close the jaws to grip the saidopposite edge of the plate and then the jaw members are moved relativeto the cylinder to tension the plate on the cylinder.

5. In a plate clamping device for securing a flexible printing plate onthe periphery of a cylinder, means for securing an edge of the platerelative to the cylinder, a plurality of first jaw members pivotallysupported relative to the cylinder and having first jaws to engage theopposite edge of the plate on the cylinder, a plurality of second jawmembers pivotally supported on the first jaw members and having secondjaws cooperable with the first jaws to engage the said opposite edge ofthe plate on the cylinder,

a rotatable shaft having members for contacting saidsecond jaw membersto open the jaws, and pressure-imparting means operable in opposition tothe shaft and its members and continuous'ly coacting with each pair ofjaw members for closing the jaws and tensioning the plate when the shaftis rotated in a direction to release the jaw members.

, to the cylinder, a first jaw member pivotally secured relative to thecylinder and having a first jaw to engage the opposite edge of the plateon the cylinder, a second jaw member pivotally connected to the firstjaw member and having a second jaw cooperating with thefirst jaw toengage the said opposite edge of the plate on the ing with the firstjaws to engage the said oppocylinder, a member movable to and fromengagement with the second jaw member, and pressure-imparting meansoperably engaging the second jaw member between the pivotal connectionsof the first jaw member and the point of engagement of the said movablemember with the second jaw member, the pressure-imparting means beingoperable in opposition to the said movable member to maintain the jawsin platereceiving relation until the said opposite edge of the plate isgripped between the jaws responsive to movement of the said movablemember and to tension the plate on the cylinder upon further movement ofthe said movable member.

'7. In a plate clamping device for securing a flexible printing plate onthe periphery of a cylinder, means for securing an edge of the platerelative to the cylinder, a first jaw member pivotally connected to thecylinder and having a first jaw to engage the opposite edge of the plateon the cylinder, a second jaw member pivotally connected to the firstjaw member at a point removed from the pivotal connection of the firstjaw member with the cylinder and having a second jaw cooperating withthe first jaw to engage thesaid opposite edge or the plate on thecylinder, a movable member engaging the second jaw member between thesaid pivotal connections, and pressure-imparting means operable inopposition to the said movable member and oper- I ably engaging thesecond jaw member between the pivotal connection of the first jaw memberwith the cylinder and the point 01' engagement of the movable memberwith the second jaw member to thereby maintain the jaws inplate-receiving relation until the said opposite edge of the plate isgripped between the jaws responsive to movement of the said movablemember and to tension the plate on the cylinder upon further movement ofthe movable member.

8. In a plate clamping device for securing 9.

otally connected at one terminal to the cylinder and having a first jawto engage the opposite edge of the plate, a second jaw member pivot-.

flexible printing plate on the periphery of a cylinder, a rotatableshaft, a roller rotatably supported by the shaft and engaging the secondjaw member between the said pivotal connections and movable relative tothe second jaw member upon rotation of the shaft, and apressure-imparting member operable in opposition to the roller andyieldingly engaging the second jaw member between the pivotal connectionof the first jaw member with the cylinder and the point of engagement ofthe roller with the second jaw member to maintain the jaws inplatereceiving relation until the said opposite edge of the plate issecurely gripped between the jaws responsive to movement of the rollerby rotative movement of the shaft and to then move the jaw membersrelative to the cylinder upon further rotative movement of the shaft totension the plate on the cylinder.

9. In a plate clamping device for securing a flexible printing plate onthe periphery of a cylinder, means for securing an edge of the platerelative to the cylinder, a first jaw member pivjaw member with the allyconnected to the opposed terminal oi. the first jaw member and'having asecond law to engage the said opposite edge of the plate,'pressure-imparting means operably engaging the second jaw member betweenthe pivotal connections of the first and second Jaw members, and amovable member operably engaging the second jaw member between thepivotal connection of the second jaw with the first and the point ofengagement of the pressure-imparting means with the second movement ofthe movable member the second jaw member is moved by the pressure-imparting means about its pivotal connection with the first jaw member to gripthe said opposite edge of the plate and then both jaw members are"connection of the first" moved about the pivotalcylinder to tension theplate on the. cylinder.

10. In a plate clamping device for securing a flexible printing plate onthe periphery or a cylinder, means for securing an edge of the platerelative to the cylinder, 9, first jaw member pivotally connected at oneterminal to the cylinder I and having a first jaw to engage the oppositeedge of the plate, a second jaw member pivotally connected to theopposed terminal of the first jaw member and having a second jaw toengage the saidopposite edge of the plate, pressure-imparting meansoperably engaging the. second jaw member between the pivotal connec-'tions of the first and second jaw members, and

a movable member operably engaging the sec ond jaw member between thepivotal connection of the second jaw with the first and the point ofengagement of the pressure-imparting means with the second jaw memberwhereby upon movement of the movable member-outwardly towards thepivotal connection of the second jaw member with the first the secondjaw member is moved by the pressure-imparting means about its pivotalconnection with the first to grip the Y said opposite edge 01' the plateand then both J'aw members are moved about the pivotal connection of thefirst jaw member with the cylinder to tension the plate on the cylinder.

WILLIAM F. HUCK.

jaw member whereby upon I

